ggplot draw a black box without separation between bars-CodePudding

I have the following chart

year <- 2022:2026
data <- 15:11
data2 <- 10:6
data3 <- 1:5

dat <- tibble(year, data, data2, data3)
data <- dat %>% group_by(year) %>% pivot_longer(all_of(starts_with('data'))) %>% ungroup() %>%  
  mutate(first_categ = case_when('data2'==name | 'data3'==name ~ value,
                           TRUE ~ 0L))
ggplot(data, aes(x = year, fill = name)) 
  geom_bar(aes(y = value), stat = 'identity', position = 'stack') 
  geom_col(aes(y=first_categ), alpha = 0, color = 'black', size = 2)

I'd like to have a separation between the two first colors (data2 and data3) and the rest because for me, these colors belong to the same category.

Is it possible to remove the intermediate horizontal separation between the blue and green?

CodePudding user response：

This is trickier than you'd imagine. Effectively you need to map to different aesthetics and fake the guides to get this effect:

ggplot(data, aes(x = year))  
  geom_col(aes(y = value, color = "data"), fill = "#F8766D", 
           position = 'stack')  
  geom_col(aes(y = value, fill = name), position = "stack", 
           data = subset(data, name != "data"))  
  stat_summary(fun = sum, aes(y = first_categ), color = 'black', 
           alpha = 0, size = 2, geom = "bar")  
  labs(color = "name")  
  scale_fill_manual(values = scales::hue_pal()(3)[-1], name = NULL)  
  guides(fill = guide_legend(override.aes = list(color = "black", size = 1.5),
                             byrow = TRUE),
         color = guide_legend(order = 1))  
  theme(legend.margin = margin(20, 0, 20, 0),
        legend.key.size = unit(10, "mm"),
        legend.spacing.y = unit(-1.5, "mm"),
        legend.box.background = element_blank(),
        legend.background = element_blank(),
        legend.title = element_text(margin = margin(0, 0, 20, 0)))